Patients with Parkinson's disease and a history of falls have decreased cerebellar grey matter volumes in the cognitive cerebellum.

The objective of this study was to determine if cerebellar gray matter (GM) structure differs between fallers and non-fallers with Parkinson's disease (PD) and their respective association to cognitive function. A total of 48 fallers and 63 non-fallers with PD were identified from the Parkinson's Progression Markers Initiative database. Fallers were categorized as those who self-reported a fall within the past year. Unified Parkinson's Disease Rating Scale-III (UPDRS-III), Montreal Cognitive Assessment (MoCA), Trail Making Test parts A (TMT-A) and B (TMT-B) scores were collected for each patient. Cerebellar GM volumes were derived from magnetic resonance imaging data. Analyses of covariance were used to compare group differences. Partial Pearson's correlations were used to assess the relationship between cerebellar GM volumes to UPDRS-III and cognitive outcomes. Significance was set at P ≤ 0.01. Fallers had significantly decreased GM volumes in lobules V, Crus-1, Crus-2, and VIIb (P<0.01). Cerebellar GM volumes in non-fallers demonstrated little-to-no relationship with UPDRS-III, MoCA, and TMT-B (P>0.01). However, TMT-A performance demonstrated significant, fair association to GM volumes in lobules I-IV, V, VI, Crus-1, and Crus-2 (r=-0.44 - -0.34, P<0.01) in non-fallers. Patients with PD and a history of falls have significantly decreased GM volumes in cerebellar lobules associated with cognitive functions. However, these lobule volumes become disassociated with cognitive function compared to non-fallers.